To assist in understanding the present invention and its various aspects, these specifications and their attached claims will refer to certain geometrical terms such as up, down, horizontal and vertical, forward and backward. The reference point to such geometrical directions should be taken to be a human foot. Thus for example, the term forward should be construed as extending from the heel substantially in the general direction of the toes, and backward refers generally to the opposite direction. Similarly the term horizontal should be construed as the general plane on which normal foot at rest, and planes parallel thereto, with the heel defining a reference plane commonly referred to as bottom. Similarly the term vertical extends at or about 90 degrees to the horizontal plane, and upward or downward to directions extending from the reference plane, with upwards implying the direction towards the knee. However as human legs and feet do not follow clear geometrical shapes the terms also extend to angles different from 90 degrees and to surfaces diverting form the flat plane, or generally to that which the person skilled in the art will recognize as the customary and ordinary meaning as relating to the human anatomy of the foot, with the heel being a reference point.
Ankle foot instabilities can be generally categorized in two ways: Medial Instability and Lateral Instability.
The term “medial instability” has been described several different ways within different professions and in different areas of the country. Orthotists commonly refer to this combination of anatomical conditions as “IRD”; internal rotary deformity. This condition describes the internal rotation of the tibia in relation to the foot. The term Internal should be construed to mean as viewed downward on the cross-section of the tibia, the forward edge moves medially. Most often the clinical findings for this are: forefoot abduction, hindfoot valgus, collapsed or partially collapsed medial longitudinal arch. Other professions have referred to this condition as flat foot, pes plantus, eversion and excessive pronation. The orthotic treatment for Medial instability is challenging. As the body weight exerts strong forces which need to be controlled, the condition is often only partially correctable.
Similarly, definitions and names abound for the term “Lateral Instability”. The common description is “twisting of the ankle”. The foot is inverted excessively to the point at which the weight line falls to the lateral side of the mid-tarsal joint and the hindfoot and forefoot are to the medial side of the tibia. Orthotists commonly refer to this condition as External Rotational Deformity (ERD). This condition is sometimes characterized by a verrous hindfoot, an adducted forefoot and a supinated midfoot. Pes cavous or excessive supination or excessive inversion are other common names for lateral instability.
Common treatment for Lateral instability dictates inter alia the use of a brace. Common brace designs may be seen in the sports industry. These can be made of soft flexible material or of rigid plastic. Such braces provide some protection to the user by reducing the extent of injury from twisting of the ankle.
Some existing solutions provide support for the foot and ankle, but lack an articulation, therefore restricting the plantarflexion/dorsiflexion movement of the ankle. Other articulated designs commonly have tolerance issues with pressure on the lateral malleolus or don't recruit the benefits of stability one can get from controlling this part of the foot and ankle.
Common treatment for Medial instability dictates inter alia the use of a brace or orthotic foot inlay. Common brace designs have been provided by Orthotists and Podiatrists. These designs are generally custom designs. Mostly, they are constructed to have an articulation at or near the medial and lateral malleolus. This misunderstood need to locate the articulation near the malleoli has resulted in the forfeit of a strategic and effective area of control. During the stance phase, there is significant medial movement of the medial malleoli. Restricting this movement provides an opportunity for improved motion control. Old metal and leather style braces would incorporate a leather “T” strap which would be wrapped around the lateral upright and around the medial malleolus. Nowadays plastic is generally used for brace designs.
Furthermore, an orthosis takes a lot of room in the shoe and often the user of orthopedic braces faces difficulty finding shoes that are big enough to accommodate the brace and foot combination.
Within the field of podiatry, the medial instability problem is described as posterior tibialis dysfunction (PTD). The theory describes the failure of the posterior tibialis muscle and tendon to uphold the medial side of the foot. The result is a medial collapse of the midfoot, plantarflexion of the talus, and navicular and first cuniform movement downwards. Most often this is in combination to a plantarflexion contracture and external bracing solutions are partial solutions. However, orthotic inlays and braces can help reduce the amount of medial collapse and therefore significantly reduce the pain associated with the Medial instability.
The portion of the foot that goes through the most excursion during weight bearing for a Medial Instability patient, is the medial malleolus. Effective control of the movement of the medial malleolus is therefore highly desirable. However, most brace designs to date avoid movement control of the medial malleolus, because of general lack of supporting soft tissue over this bony prominence. The lack of soft tissue makes the medial malleolus intolerant of high corrective pressures. Yet, if controlled, the medial malleolus likely provides the most effective location in the management of Medial Instability.
Therefore, there is a clear and heretofore unanswered need for brace design that will reduce the shoe size, while providing good support and motion control, preferably with controlling the medial or lateral malleolus as needed. The present invention is aimed at providing such a brace.